Centennial response of Greenland’s three largest outlet glaciers

Shfaqat Khan , Anders Bjørk , Jonathan Bamber , Mathieu Morlighem , Michael Bevis , Kurt Kjær , Jeremie Mouginot (1) , Anja Løkkegaard , David Holland , Andy Aschwanden , Bao Zhang , Veit Helm , Niels Korsgaard , William Colgan , Nicolaj Larsen , Lin Liu , Karina Hansen , Valentina Barletta , Trine Dahl-Jensen , Anne Sofie Søndergaard , Beata Csatho , Ingo Sasgen , Jason Box , Toni Schenk

1 IGE - Institut des Géosciences de l’Environnement

The Greenland Ice Sheet is the largest land ice contributor to sea level rise. This will continue in the future but at an uncertain rate and observational estimates are limited to the last few decades. Understanding the long-term glacier response to external forcing is key to improving projections. Here we use historical photographs to calculate ice loss from 1880–2012 for Jakobshavn, Helheim, and Kangerlussuaq glacier. We estimate ice loss corresponding to a sea level rise of 8.1 ± 1.1 millimetres from these three glaciers. Projections of mass loss for these glaciers, using the worst-case scenario, Representative Concentration Pathways 8.5, suggest a sea level contribution of 9.1–14.9 mm by 2100. RCP8.5 implies an additional global temperature increase of 3.7 °C by 2100, approximately four times larger than that which has taken place since 1880. We infer that projections forced by RCP8.5 underestimate glacier mass loss which could exceed this worst-case scenario.

Domaines: Sciences de l'environnement

Shfaqat Khan, Anders Bjørk, Jonathan Bamber, Mathieu Morlighem, Michael Bevis, et al.. Centennial response of Greenland’s three largest outlet glaciers. Nature Communications, 2020, 11 (1), ⟨10.1038/s41467-020-19580-5⟩. ⟨hal-03026187⟩